Drought events are increasing, at least in Africa, and there is naturally more and more
discussion about their mitigation and management. At the same time, the existing drought
indices do not meet the special requirements of African drought managers. The water
balance methods are far too complex and require a large number and many types of
data that are simply not available. The statistical indices 1) do not fully comply with
the fundamental requirements of the definition of drought, because they mostly consider
only one or two parameters; 2) do not consider the persistence of the stress periods,
and 3) require continuous data observation without gaps. In the absence of easy-to-use
monitoring tools and methodologies, often rudimentary methodologies are used, like the
annual rainfall amount. As even a few months, sometimes a few weeks of unfavorable
climate conditions cannot be well tolerated by the plants, it is obvious that shorter period
drought analysis is needed, which should also offer the possibility to be extended to
annual or even longer periods.